Is there pseudoprogression in secondary glioblastomas?

Area of Science:

• Neuro-oncology
• Radiation Oncology
• Medical Genetics

Background:

• Pseudoprogression (PP) is a common challenge in glioblastoma (GBM) treatment.
• Data on PP incidence in secondary glioblastomas (sGBM) is limited compared to primary GBM.
• Understanding PP in sGBM is crucial for accurate treatment assessment.

Purpose of the Study:

• To evaluate the frequency of pseudoprogression (PP) in adult patients with secondary glioblastomas (sGBM).
• To investigate potential associations between PP and MGMT promoter methylation, IDH mutations, or 1p/19q codeletion in sGBM.
• To compare PP incidence in sGBM with known rates in primary GBM.

Main Methods:

• Retrospective analysis of adult sGBM patients receiving chemoradiation therapy (CRTx) with temozolomide (TMZ).
• Assessment of PP using Response Assessment in Neuro-Oncology (RANO) criteria.
• Correlation analysis with MGMT promoter methylation, IDH mutations, and 1p/19q codeletion status.

Main Results:

• No pseudoprogression (PP) was observed in any of the 15 evaluable sGBM patients.
• PP did not occur in patients receiving concomitant or sequential CRTx with TMZ, regardless of MGMT or IDH status.
• Median follow-up was 3.4 years, with a median overall survival of 18.2 months.

Conclusions:

• The incidence of pseudoprogression (PP) appears very low in secondary glioblastomas (sGBM) treated with chemoradiation.
• MGMT promoter methylation and IDH mutations did not correlate with PP in this sGBM cohort.
• Findings highlight distinct patterns of PP between primary and secondary glioblastomas.